MikeC.86Roc

iTrader: (10)

What is the small fitting directly below the fitting for crankcase evacuation supposed to go to? Its the bottom of the 2 behind the TPS sensor..

Kevin91Z

iTrader: (1)

It goes to the fuel vapor canister. There should be a plastic line from the TB to it. On a Camaro, its on the driver's side.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

MikeC.86Roc

iTrader: (10)

Bam, thats it! Thanks Kevin

Matt_Ky

I just bought a 1985 TPI and was trying to figure out the same thing. What is the top fitting for?
BTW, both of the fittings behind the TPS (passenger side of throttle body) have rubber hoses about 5/8". Actually, the bottom hose is somewhat smaller than the top hose.
Also, what are the two fittings at the rear of the plenum on the passenger side? They are about one inch apart and the one closest to the firewall is the larger of the two.
The last one Im trying to identify is at the rear of the plenum on the drivers side.
Does anybody know of a web site that would help me identify all the sensor connections, vacuum lines, etc on the TB, plenum and intake manifold?
Thanks

Jason Aschle

1985 TPI --- just behind the TPS, top goes to the crankcase vent tube, lower goes to the charcoal canister, rear of plenum, passenger side, on port is for the fuel pressure regulator, other is for A/C & Cruise control, and on the drivers side rear, the port is for the power brake booster. If I am not clear, let me know...

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1991 Camaro TPI, 355ci. Sportsman 11 heads, LT-4 Hot cam,Pete Jackson gear drive, on,and on, and on... 13.6 @ 102.5 with a 2:73 open rear, no traction, no tuning, no practice.

1985 California Edition IROC red, polished TPI and polished wheels, otherwise completely stock 305ci. 700r4

1991 fullsize Blazer 4-wheel drive, 350,700r4, Pro Comp lift, K&N, TBI spacer, 3" Catco cat, 3" cat back Flowmaster, etc....

Matt_Ky

Jason,
Thanks a million man, that helps! The last fitting Im trying to identify is a small port on the bottom of the TB on the drivers side. Its about 1/8" diameter and 3/4" long.
BTW, the two at the rear of the plenum passenger side, which port is for the fuel pressure regulator, the one closest to the front of the engine or the one closest to the firewall?
Thanks again Jason!

Jason Aschle

The small tube on the underside of the throttle body is for a vaccum line connecting to the EGR. As for the ports on the rear, it makes no differance which you use for the regulator, I have mine hooked to the back port (closest to the firewall) but it does not matter. Do you have all of the vaccum tubes? If so, the rubber tips may be different sizes, just go about it that way. Feel free to ask any other questions, this website can teach you anything you need to know about a 3rd gen....

http://sc3gfb.org/members/jason.html



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1991 Camaro TPI, 355ci. Sportsman 11 heads, LT-4 Hot cam,Pete Jackson gear drive, on,and on, and on... 13.6 @ 102.5 with a 2:73 open rear, no traction, no tuning, no practice.

1985 California Edition IROC red, polished TPI and polished wheels, otherwise completely stock 305ci. 700r4

1991 fullsize Blazer 4-wheel drive, 350,700r4, Pro Comp lift, K&N, TBI spacer, 3" Catco cat, 3" cat back Flowmaster, etc....

Matt_Ky

Jason,
thanks again! fortunately, I have the complete wiring harness, ECM (not going to use) and motor, however, all hoses,
vacuum lines, etc had been removed.
Im converting this MAF TPI to speed density so Im thinking I can "T" off either the A/C vacuum port or the crankcase vent port on the plenum to run a line to the MAP sensor.
Matt

Jason Aschle

The MAP sensor should have a port dedicated just for it. I have an older style plenum with the 2 rear ports, newer style has 3, I have the fuel regulator using one of it's own, and the MAP sensor is using the other. I "T-d" into the brake booster hose for my A/C. I tried to run the car with the MAP running with the A/C on the same port, but the sensor did not read correctly and it ran horrible. You state you have a harness and computer that won't be used, if you wish to get rid of it, please e-mail me with the specs on it and a price... Thanks.

http://sc3gfb.org/members/jason.html



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1991 Camaro TPI, 355ci. Sportsman 11 heads, LT-4 Hot cam,Pete Jackson gear drive, on,and on, and on... 13.6 @ 102.5 with a 2:73 open rear, no traction, no tuning, no practice. Car is pictured in Chevy High Performance magazine, June 2000 issue.

1985 California Edition IROC red, polished TPI and polished wheels, otherwise completely stock 305ci. 700r4

1991 fullsize Blazer 4-wheel drive, 350,700r4, Pro Comp lift, K&N, TBI spacer, 3" Catco cat, 3" cat back Flowmaster, etc....

Kevin91Z

iTrader: (1)

You know what is crazy? My MAP sensor is T'd with the A/C and cruise control, and its been that way since I've had the car. I believe it had a blower on it sometime before I got it. The port in the back is the fuel pressure, and the front port was blocked off. I see normal vacuum, even with a ZZ4 cam, but since I'm putting in an LT4 hot cam, I'm redoing that and putting the MAP sensor on its own port. But, remember they're all getting their vacuum from inside the plenum, so why does it matter if they're connected inside or outside the plenum?

Matt_Ky

I think I'll try the MAP and AFPR lines dedicated and "T" off the brake booster for A/C.

Jason,
The ECM has the following identification #'s:
16052541
Bosch 14080620 (6 wire connector)

Im not sure yet which route Im going as far as the wiring harness when switching to SD, ie, try to use the exisiting 1985 harness, order 1990-2 harness thru dealer or use an aftermarket one. The '85 harness is 100% complete I do know that.
As far as the ECM whatever its worth plus shipping if you need it. All of the these components were functional when the guy wrecked his Camaro recently.
Thanks all!